It's all well and good that, early in 21 Jump Street, a police chief (Nick Offerman) informs rookie cops Jenko (Channing Tatum) and Schmidt (Jonah Hill) that they're reviving an old undercover-in-high-school program from the 1980s, because the only idea anyone can come up with now is to "recycle shit from the past." But what do we really expect from movies that cash in on nostalgia for old TV shows, cartoons, toys and board games? Is it enough for a brand-name reboot to wink at us and say, "Yep, we're out of ideas, but at least we're honest about it?"

Every once in a while, a filmmaking team comes up with a quirky enough perspective that the revival of a title seems not just forgivable, but almost inspired. The Brady Bunch Movie may be the standard-bearer in that respect, a shiny satire that acknowledged everything that was beloved about the blended family of hopeless squares by throwing them into a completely new cultural context. Last year's The Muppets similarly felt more built on genuine affection than cynical marketing calculation.

Yes, there are ways to convince us that throwing the title of an old TV series on a big screen actually had a point — and the bulldozer of hilarity that is 21 Jump Street belongs in that conversation.

In this cockeyed take on the 1987 to 1991 FOX TV show that made Johnny Depp a star, we first meet our heroes in 2005 as high-school seniors: Jenko the dumb jock, Schmidt the socially inept nerd. The former antagonists find themselves classmates once again at the police academy, where they form an unlikely partnership to maximize their respective physical and mental talents. That partnership extends to their first big assignment: joining the revived program sending young-looking cops undercover as high school students, and trying to find out who's dealing a new designer drug known as "H.F.S." (for "Holy Fucking Shit").

Screenwriter Michael Bacall (Scott Pilgrim vs. The World) could have gone for straightforward buddy-cop action, and he hits plenty of great targets in that respect, starting with Ice Cube loudly embracing the stereotypical "angry black captain." While Hot Fuzz got to a lot of the material first, Bacall does plenty with his affectionate skewering of everything from training montages to the tension between partners.

But the real brilliance here comes from how it exploits the high-school setting. It's amusing enough that Jenko and Schmidt wind up adopting roles completely opposite from those they had as teens. Better yet is turning the cops' inability to blend in, into a commentary on the ridiculous rate of change that makes it so their seven-years-gone high-school experience might as well have been in the 1950s. The film has a blast showing how the generation gap no longer waits for a generation.

It's true that the filmmakers push further into over-the-top crude than necessary. But 21 Jump Street finds its humor in so many places — from the twisted hallucinogenic effects of the new drug, to a performance by Tatum that finds depths of charm previously unimaginable, to the way it introduces the inevitable nods to its source material — that the only really appropriate word is "inspired."

That's a word you generally don't associate with something that just recycles "shit from the past." But as Jenko and Schmidt's environmentally aware classmates would be quick to point out, recycling can be cool.